Responses of subcultured rat aortic smooth muscle myocytes to vasoactive agents and KCl-induced depolarization.

We have developed a culture system in which a single-mass primary culture can be used for as long as 6 wk as a source of subcultured smooth muscle myocytes for the study of the changes of their shape upon addition of vasoactive agents (angiotensin, vasopressin, norepinephrine, and serotonin) and KCl depolarization. Responses of subcultivated myocytes were shown to be reproducible with time in primary culture before subculture and consistent with responses of thoracic aorta to the same agents. Effect of KCl depolarization could be blocked with calcium antagonist PN 200-110. Consistently, the presence of calcium L-channels was shown using whole cell patch-clamp recordings. A comparative study of the responses of myocytes derived from two different segments of the thoracic aorta showed that these cells displayed responses with different maximal amplitudes and the same potencies according to their topological origin in the vessel.